In general, MEMS technology has been utilized to construct infrared light detectors. One such light (IR photonic) detector includes a MEMS structure with a capacitor and a cantilever arm. The capacitor has a fixed plate and a mobile plate. The cantilever arm has a first end, which is fixed to a substrate, and a second end, which is fixed to the mobile capacitor plate. The cantilever arm also includes a bimorph portion that bends in response to being heated by absorption of infrared light. Bending of the bimorph portion displaces the mobile plate in a manner that changes the distance between the mobile and fixed plates of the absorber. Thus, illumination of the MEMS structure by infrared light produces a measurable change in an electrical property of the structure, i.e., the capacitance of the capacitor. By measuring variations in such capacitances, the light detector is able to determine the intensity of infrared light illuminating each MEMS structure, i.e., each pixel element of the detector.
Another common type of thermal radiation detector is the un-cooled micro-bolometer. In general, a micro-bolometer comprises as thin film absorbing detector and a thermal isolation structure. Incident radiation absorbed by the detector induces a temperature increase that further result in variations of the electric conductivity of the thin film detector. The electrical conductivity is used to determine the intensity of the incident radiation.
The principal limitations of detectors including cantilever and micro-bolometer type structures arises from the electrical connections required to read the temperature variations or changes in electrical characteristics (e.g., resistance, capacitance) induced by incident radiation. Moreover, the complexity of manufacturing pixel interconnections and the readout circuitry has maintained the manufacturing costs of the detector structures prohibitive for many applications. Furthermore, these electrical interconnections impair the thermal isolation between the pixels and the readout system and, as a result, limit the thermal sensitivity of the detector. Semiconductor and quantum electronic detector methodologies are very prone to self-generated and external noise sources that lower the systems sensitivity and require complex and expensive methods to mitigate the problems.